The use of reinforcing structures in motor vehicles is known. One such example is crush countermeasures, such as roof crush countermeasures. Roof crush countermeasures are used for absorbing impact energy and protecting motor vehicle occupants in the event of a rollover event. These crush countermeasures are included within the hollow portions of a motor vehicle, such as in the roof assembly. Roof crush countermeasures, as well as other reinforcing structures, have previously been designed to provide a structure that fits within the hollow spaces to be reinforced.
In one embodiment, for hollow parts of a motor vehicle, a basic load-bearing article is used in conjunction with a foamable material. The load-bearing article serves primarily to retain the foamable material in the hollow part. Next, the hollow part is filled with foam to its full volume, and the expanded foam material provides the connection to the wall and thus the absorption of force and distribution of load. The reinforcement characteristics are based on the material properties of the foam. However, these prior art reinforcement systems require a chemical reaction that must be adapted to the production process of the vehicle, particularly in terms of the incident temperatures. The reinforcement function thus depends on accurate and constant adherence to the process parameters. Another disadvantage is that the structural parts can no longer be disconnected from one another easily, making recycling more difficult. In addition, completely filling the space with foam brings about a more or less homogeneous reinforcement effect, without the ability to take three-dimensional varying design requirements into account.
In another prior art embodiment, some crush countermeasure systems include steel stampings that are fixed to the sheet metal via thermoset adhesive. The adhesive will activate and expand as the body goes through the ovens that bake the paint. This system is not optimal. The stampings are heavy and excessive adhesive is applied to assure a solid bond from the countermeasure to the body.
Accordingly, it would be beneficial to provide a lightweight crush countermeasure that provides comparable ability to absorb impact energy and/or protecting motor vehicle occupants as metal roof crush countermeasures. It would also be beneficial to provide a crush countermeasure that may be easily manufactured and used in a motor vehicle without the use of additional processing steps.